Bar joist



T. A. LUCY BAR JOIST May 2, 1933.

2 Sheets-Sheet Filed Aug. 23, 1928 0 Flo/ms A Lucy,

aewm.

May 2, 1933. T. A. LUCY 1,907,209

BAR JQIST Filed Aug. 23, 1928 2 Sheets-Sheet 2 W Iii GLrM e/n/Bor/I Tnarms A. 404v,

Patented May 2, 1933 UNETED STAES i THOMAS A. LUCY, F BIRMINGHAM, ALABAMA, ASSIGNOR TO INGALLQ) STEEL PRODUCTS COMPANY, OF BIRMINGHAM, ALABAMA BAR JOIST Application filed August 23, 1928. 'Serial No. 301,639.

This invention pertains to bar joists, such as are usually constructed in trussed form of relatively light bar metal.

One of the objects of this inventionls to provide a bar joist and a method of manufacto sizes and various combinations of standard members may be assembled. to form joists of different sizes.

In accordance with the present invention, the upper chord member is formed of a bar 1 of rolled structural iron or the like, having a T-section. These upper chord members may be made up in several standard lengths, according to the standard lengths of span of joistsof this type. Each end of the upper chord member 1 is provided with a bearing member 2 in order Another object is to provide a bar joist with an improved end bearing portion.

Another object is to provide improved means for mounting and securing a bar joist' of the typein question.

Further objects will appear from the following description, taken in connection with 20 the accompanying drawings, in which- 7 Figure 1 is a side view of a bar joist embodying this invention;

Figure 2 is a fragmentary perspective view of the same, illustrating the manner of mounting the same;

Figure 3 is a detail of one end of the joist in place, showing the manner of securing the same;

Figure 4- is a section on line H of Figure 3;

Figure 5 is a detail of the end of the upper chord member, showing the construction of the same; and

Figures 6 and 7 show details of the lower chord elements and of the web elements, respectively.

In the manufacture of bar joists of the type under consideration, it is necessary to be prepared to furnish a quantity of joists of any one of a considerable range of sizes. The sizes vary in the length of the span and also in the depth of the joist in order to meet the demands of the load which the joist is to carry. It is desirable, therefore, to provide a method of construction which will lend itself readily to the building of a joist of any size within a certain range out of standard units. In accordance with this invention, therefore, a system is provided wherein the various truss members of the oist may be standardized as to support the same at its ends. The bearing'member 2 is made up of another section of material, having a T-shape crosssection,. and is joined web to Web with the bar 1, as illustrated in Figure 5. The bar 1 and the member 2 are provided with matching dovetails 3 at the edges of their Webs. These dovetails are fitted into one another, and the two pieces are then welded together at the dovetailed joint. Thus, the end of the upper chord member is given an I-section, so as to provide an improved bearing for the end of the joist, and one which will withstand transverse bending. I 1

The Web of the joist may be made up of any number of web elements 4, as shown in Figure 7. These elements are constructed of bar iron bent to angular form, as shown, so as to provide a panel member adapted to form one panel of the web of the truss. These members may be made of various standard lengths, so as to provide panels of difierent lengths, which may be applied to form oists of different lengths.

The lower chord is formed of two chord elements 5, also of bar iron, bent upwardly at one end. These parts may also be made up in diiferent lengths for different lengths of truss.

These parts are assembled as illustrated in Figures 1 and 2. The web members 4 are welded to the web of the upper chord member 1 at their upper ends and at their lower ends the lower portions are welded to the lower chord formed by a pair of elements 5 assembled in reversed relation relatively to one another. That is, the uppwardly bent ends Got the chord members are placed at 100 opposite ends of the joist. The diagonal member 7 of the end panel member 4 takes a position parallel to the end 6, as shown in Figure 2. The upper ends of the panel members 4 are placed alternately on opposite sides of the web of the chord member 1 and welded thereto. During the welding operation, pressure may be applied at these points so as to press the panel member into the web of the chord 1, as illustrated at 8. This insures a good welded joint at these points. The members 6 and 7 are also placed on opposite sides of the web of the chord 1. A bar may be wired to the joist in the usual manner to support the ceiling lath.

It will be noted that the members 6 and 7 are placed so as to cross the dove-tail joint 3 so as to reinforce the same and strengthen the end section of the upper chord.

In making up joists of difierent sizes, any combination of upper chord, web and lower chord members may be assembled together. However, as standard sizes of joists vary by a small length, it is convenient to provide means for varying the length of the joist by a small amount. Such variation is often as small as six inches- In accordance with this invention, therefore, panel members la are provided, constructed to give a panel length slightly greater (say, three inches) than the standard members 4. Accordingly, a joist having a length six inches greater than the standard length may be provided by inserting a panel member eta as, say the second panel from each end of the joist, a corresponding extra. length of upper and lower chord member being used if required. 'The panels lar. have the same depth as the panels 4, but are slightly longer. Thus, by the insertion of two members 4a, a variationin length of six inches can be obtained without changing the dimensions of any of the other parts of the trusssuch as depth and width.

The truss may be anchored to its support, which may be a girder 9 or other suitable support, by engaging an anchor 10 in a notch 11 in the member 2. This anchor 10 is of bar iron and is bent downwardly over the edge of the girder 9 so as to provide a hook adapted to hold the joist in place. This anchor not only functions to secure the joist in place, but also assists in carrying the load thereon. As the load has a tendency to cause the beam to sag, the anchors 10 will be placed under tension, thereby applying tension to the upper chord member so as to balance a part of the compression stress therein. This is the result of placing the anchor 10 near the, top of the truss and above the center of gravity of, its cross-section.

Figures 3 and l show how the I-shape end of the upper chord assists in spreading the load over a greater area of the support on which it rests. The concrete floor 12 may be so arranged that the concrete is poured around the ends of the oists, as indicated at 13 in Figure 3. Thus, the ends are completely imbedded in concrete so that the upper flange of the chord member 1, as well as the lower flange, is active in transmitting the load to the support. In other words, the upper flange is supported by the concrete which transmits the load to the support along an area defined by the dotted line 14:, in Figure 4. Accordingly, the concentration of load upon the supports is considerably reduced.

It will be seen, therefore, that this invention accomplishes its objects. It provides a method of manufacture in which the joist is made up of unit elements. These unit elements may be made in a series of standard sizes and assembled in various combinations so as to vary the size of the oist. The length of one or more individual panels may be changed so as to adjust the length of the joist. In this way a considerable range oi lengths can be obtained with the same size upper and lower chords and two sizes of panel elements.

The method of supporting the truss as shown in, Figures 3 and ltakes advantage of the I l-section of the end of the upper-chord so as to reduce the concentration of load at the supports.

hile this joist has been described as a unitary, structure, it is obvious that certain parts or the complete combination may be useful without other parts thereof, and the use oi such sub-combinations is contemplated by this invention.

-t is further obvious that various changes may be made, within the scope of the appended claims, in the details of construction without'departing from the spirit of this invention. it is, therefore, to be understood that this invention is not to be limited to the speciiic details shown and/or described.

Having thus described the invention, what is claimed is: r V.

1. In the artof making bar joists, the method comprising, forming a series of substantially full length upper and lower chord members including members of different lengths for different spans, and a series of web members in separate panel units of different lengths, and permanently assembling selected chord members with panel members of selected lengths in accordance with the required size of the joist.

2. In the art of making bar joists, the method comprising, forming substantially full length upper and lower chord members,-

and a series of web members in separate pan cl units of '(llllQlQllll lengths, and permanently assembling said chord members and panel units of selected lengths in accordance with the required size or the joist, said lower chord membersbeing assembled in reversed relation to one another. 7

3. In the art of making bar joists, the

method comprising, forming a series of substantially full length upper and lower chord members including members of different lengths, and a series of web members in separate panel units of different lengths, and permanently assembling selected chord members with panel members of selected lengths in accordance with the required size of the joist, said lower chord members being assembled in reversed relation to one another.

4:. A bar joist, comprising, an upper chord member having a T-section, a web member secured at its upper portion to the web of said chord member, a lower chord member secured to the lower portion of said web member, and a bearing member having a T- section and having its web dove-tailed to the web of said upper chord member.

5. A bar joist, comprising, an upper chord member having a T-section, a web member secured at its upper portion to the web of said chord member, a lower chord member secured to the lower portion of said web member, and a bearing member having a T-section and having its web dove-tailed and welded to the web of said upper chord member.

6. A bar joist, comprising, an upper chord member having a T-section, a web member including a series of web elements each having parts secured to opposite sides of the web of said chord member, and a lower chord member secured to the lower portions of said elements on opposite sides thereof.

7 A bar joist, comprising, an upper chord member having a T-section, a web member including a series of web elements each bent to angular form and having its ends secured to opposite sides of the web of said chord member, and a lower chord member secured to the lower portions of said elements on opposite sides thereof.

8. A bar joist, comprising, an upper chord member having a T-section, a web member including a series of web elements each having diagonal and upright parts secured to opposite sides of the web of said chord member, and a lower chord member including a pair of bent chord elements assembled in reverse relation to one another and secured to the lower portions of said web elements on opposite sides thereof.

9. A bar joist, comprising, an upper chord member having a T-section, a web member including a series of web elements each bent to angular form to provide a diagonal and an upright and having its ends secured to opposite sides of the web of said chord member, and a lower chord member including a pair of bent chord elements assembled in reverse relation to one another and secured to the lower portions of said web elements on opposite sides thereof.

10. A bar joist, comprising, an upper chord member having a T-section, a web member secured at its upper portion to the web of said chord member, a lower chord member secured to the lower portion of said web member, and a bearing member having a T- section and secured web-to-web to the end of said upper chord member and reinforced by said lower chord member.

11. A bar joist, comprising, an upper chord member having a T-section, a web member secured at its upper portion to the web of said member, a lower chord member secured to the lower portion of said web member, a bearing member having a T-section and 113V? ing its web dove-tailed to the web of said upper chord member, and means for reinforcing said dove-tailed web.

12. A bar joist, comprising, an upper chord member having a T-section, a web member secured at its upper portion to the web of said chord member, a lower chord member secured to the lower portion of said web member, and a bearing member having a T- section and having its web dove-tailed and welded to the web of said upper chord mem ber, said lower chord member being welded across the dove-tailed joint in said Web.

13. A bar joist, comprising, an upper chord member having a T-section and provided with a bearing at each end, a series of individualweb panels each formed of an angularly bent bar providing a diagonal and an upright, said diagonal and' upright of each panel member being secured to opposite sides of the web of said chord member, and a lower chord member formed of a plurality of bars each bent at one end to form an end diagonal rising to one of said bearings, said chord bars being arranged in reverse relation to one another and secured to said web panels.

14. A bar joist, comprising, an upper chord member having a T-section and provided with a bearing at each end, a series of individual web panels each formed of an angularly bent bar providing a diagonal and an upright, said diagonal and upright beingsecured to end panels rising to said bearings to form' part of the lower chord.

In testimony whereof I afi'ix my signature this 1st day of August, 1928.

THOMAS A. LUCY. 

